The Pure HU has a male SMB aerial connector, which supplies 12V down the centre pin of the co-ax.
I bought the DAB film antenna from Halfords, as recommended by Edinburgh. I told the Halfords people (friendly and knowledgeable) that I had the Pure Highway and they immediately told me that this antenna is compatible. It also specifically says that if power is supplied by the HU, it should be sufficient. The HU warns that you shouldn't use a separate power feed unless the antenna can't pick up the one from the centre pin.
I think first, I'll try without a separate power supply. However, if that doesn't work, the next option is to change the HU settings to turn off the on-board 12V supply and then go for a separate one.
Good. Glad that's clear. All I need now is a car to install it in... Now, what could that be...?
A Clennell classic (forgive me Jim)
Yes, that's the same advice re supply issue I received and have no issue with it.